This application determines if a highly standardized herbal extract of the leaves of the Ginko biloba tree, widely used in Europe for two decades, will benefit patients who have pain on walking due to narrowing of the arteries of the legs. A few studies done about ten years ago in Germany appeared to benefit such patients. It is important to confirm these findings and to learn how it may work. Animal studies suggest that this extract, known as EGb 761, works through very strong antioxidant mechanisms. A second action suggested is that is stimulates cells lining the inside of the arteries to produce the compound nitric oxide. These cells, known as endothelial cells, are susceptible to damage by blood cholesterol, smoking or high blood pressure and, when damaged, will allow cholesterol to deposit in arteries. Antioxidants can prevent the endothelial cell damage, therefore it is very important to know if EGb 761 works through this mechanism. These cells also produce nitric oxide naturally as a defense against injury, so an EGb 761 effect on nitric oxide would also provide benefit.